Date.prototype mutable internal properties

Mark S. Miller erights at
Fri Jul 1 18:01:15 PDT 2011

Thanks David,

Yes, this is important. The way I noticed it is that the same issue came up
for the FF implementation of WeakMaps <>. I will be proposing
the to-be-fixed Mozilla API to the committee to become the new WeakMap
proposal -- making it more consistent with Map and Set. But not at the
upcoming meeting -- it's not on the agenda.

In the meantime, <>
repairs this and many other problems encountered in today's almost-ES5
implementations. Except for this issue with Date and WeakMap, all the other
repairs in that file are spec non-conformances. See the kludges list at <>
for cross referencing between these repairs, various bug threads, and
Sputnik/test262 test names.

On Fri, Jul 1, 2011 at 12:28 PM, David Bruant <david.bruant at> wrote:

> Hi,
> I just wanted to put on es-discuss the concern raised by Mark Miller [1]
> about mutable internal properties of Date.prototype and that it should
> be fixed in the next version of ECMAScript.
> David
> [1]

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